Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 270557 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1257 AM EST TUE JAN 27 2015 .SYNOPSIS... STRONG LOW PRESSURE SOUTH OF NEW ENGLAND WILL CONTINUE TO SLOWLY MOVE NORTH AS HIGH PRESSURE SLOWLY BUILDS INTO THE CAROLINAS THROUGH THURSDAY. A COLD FRONT WILL MOVE ACROSS THE EASTERN CAROLINAS THURSDAY NIGHT. ANOTHER COLD FRONT WILL SWING THROUGH THE REGION ON SUNDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 1030 PM MONDAY...THE NEGATIVELY TILTED MID TO UPPER LEVEL TROF WILL EVENTUALLY CLOSE OFF OVERNIGHT INTO TUESDAY. THE 1 VORT OR S/W TROF HAVING ROUNDED THE BASE OF THIS MID TO UPPER TROF THIS EVENING...IS CURRENTLY HEADING DUE NORTH. THE DYNAMICS FROM THIS UPPER FEATURE IS AIDING THE INTENSIFICATION OF THE SFC LOW NOW OFF THE NJ-DEL COAST. THE SFC LOW WILL SLOW ITS NORTH TO NORTHEAST MOVEMENT AS IT IS CAPTURED BY THE UPPER LEVEL CLOSED LOW DURING THIS PERIOD. FORTUNATELY FOR THE ILM CWA...ALL OF THE DYNAMICS AND THE WORST SENSIBLE WEATHER CONDITIONS TO REMAIN WELL NORTH OF THE ILM CWA. THE FA TONIGHT WILL HAVE TO DEAL WITH EXCELLENT CAA UNDER INCREASING NW FLOW AS THE SFC PG TIGHTENS IN RESPONSE TO THE LOW SLOWING ITS FORWARD MOVEMENT AND BOMBING OFF THE DELMARVA AND NE STATES COASTS. AT THE MOMENT...THE CURRENT FORECAST TREND INDICATES TEMPS TO FALL STEADILY THRUOUT THE NIGHT...DROPPING TO THE MID 30S ALONG THE IMMEDIATE COAST...AND LOWER 30S AWAY FROM THE IMMEDIATE COAST. LOCATIONS ALONG AND WEST OF THE I-95 CORRIDOR COULD OBSERVE TEMPS BREAKING THE 30 DEGREE MARK...AND INTO THE UPPER 20S. INSTABILITY TYPE SHOWERS DUE TO THE CAA SFC AND ALOFT WILL CONTINUE WELL INTO THE OVERNIGHT UNTIL MOISTURE AVAILABILITY RUNS OUT TOWARD DAYBREAK TUESDAY. CHANCE POPS WILL DIMINISH TO SLIGHT CHANCE BY DAYBREAK. AS FOR PCPN TYPE...USING THE TOP DOWN APPROACH...A FEW LOCATIONS ACROSS THE ILM NC COUNTIES COULD WITNESS LIGHT SNOW FLURRIES DURING THE PRE-DAWN TUE HOURS. PREVIOUS DISCUSSION.................................... AS OF 315 PM MONDAY...SURFACE LOW PRESSURE IS DEEPENING RAPIDLY OFF THE VIRGINIA COAST...SITUATED DIRECTLY BENEATH A BEAUTIFUL BAROCLINIC LEAF ON SATELLITE IMAGERY. ALTHOUGH THIS IS NOW THE MAIN SURFACE LOW WE STILL HAVE SOME INTERESTING WEATHER COMING UP OVER THE NEXT 12 HOURS DUE TO THE COLD UPPER LOW. AT 500 MB THIS LOW IS CENTERED OVER NORTHERN NORTH CAROLINA AND SHOULD REACH THE COAST OF SE VIRGINIA A FEW HOURS AFTER SUNSET. 500 MB TEMPS AS COLD AS -26C HAVE STEEPENED LOW AND MID-LEVEL LAPSE RATES TO NEAR OR JUST BEYOND THE MOIST ADIABATIC LAPSE RATE...AND WIDESPREAD CUMULUS CLOUDS AND EMBEDDED SHOWERS HAVE BEEN THE RESULT. THIS CONVECTIVE ACTIVITY IS CURRENTLY MOST NUMEROUS FROM DILLON DOWN HIGHWAY 9 TOWARD LORIS...ALTHOUGH MODELS TRENDS SUGGEST THE BULK OF IT SHOULD SHIFT INTO SOUTHEASTERN NORTH CAROLINA AFTER DARK...AIDED BY ANOTHER VORT LOBE SWINGING ACROSS THE AREA BY 03Z/10 PM. FORECAST POPS ARE HIGHEST...UP TO 50-60 PERCENT...FROM THE STATE LINE INTO WILMINGTON...WITH LESSER POPS ACROSS THE SOUTHERN HALF OF THE PEE DEE REGION DOWN TOWARD GEORGETOWN. AFTER MIDNIGHT DRY NORTHWEST WINDS SHOULD CLEAR PRECIP AND THE BULK OF THE CLOUDS OUT OF SOUTH CAROLINA...HOWEVER RECENT MODEL TRENDS SUGGEST THE UPPER LOW WILL BE SLOW ENOUGH PULLING OUT TO THE NE THAT MOISTURE WILL CONTINUE TO CIRCULATE THROUGH AT LEAST COASTAL SE NORTH CAROLINA. AFTER 5 AM TUESDAY MORNING I HAVE SLIGHT CHANCE POPS (20%) CONFINED TO JUST PENDER COUNTY NC...AND IT IS NOT IMPOSSIBLE SOME WET SNOWFLAKES COULD MIX IN WITH ANY LINGERING RAIN AS FREEZING LEVELS COME DOWN TO AROUND 500 FEET AGL. LOW TEMPERATURES SHOULD RANGE FROM THE MID 30S NEAR THE COAST TO THE LOWER 30S INLAND. AS OF 3 PM MONDAY...SURFACE LOW PRESSURE IS DEEPENING RAPIDLY OFF THE VIRGINIA COAST...SITUATED DIRECTLY BENEATH A BEAUTIFUL BAROCLINIC LEAF ON SATELLITE IMAGERY. ALTHOUGH THIS IS NOW THE MAIN SURFACE LOW WE STILL HAVE SOME INTERESTING WEATHER COMING UP OVER THE NEXT 12 HOURS DUE TO THE COLD UPPER LOW. AT 500 MB THIS LOW IS CENTERED OVER NORTHERN NORTH CAROLINA AND SHOULD REACH THE COAST OF SE VIRGINIA A FEW HOURS AFTER SUNSET. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 330 PM...THE LOW OFF THE VIRGINIA CAPES CONTINUES TO RAPIDLY DEVELOP INTO AN IMPRESSIVE NOR`EASTER THE WILL SLOWLY PULL AWAY FROM THE FORECAST AREA. FROM THE SYSTEM THERE ARE A COUPLE OF HOURS AFTER SUNRISE IN WHICH NORTHERN PENDER COUNTY...MAINLY NORTH OF A PENDERLEA TO SURF CITY LINE...WHERE A FEW FLAKES OF SNOW MIXED WITH RAIN MAY FALL. AT THIS TIME THE CHANCE OF THE PRECIPITATION IS A VERY LOW 20 PERCENT. NO ACCUMULATION IS EXPECTED. WITH A NORTHWEST THEN NORTHWESTERLY FLOW AND A CLEAR SKY ON TUESDAY THE AREA WILL SEE HIGHS ON TUESDAY REACHING MID 40S TO AROUND 50 AND MID TO UPPER 40S ON WEDNESDAY. LOWS ARE EXPECTED TO BE IN THE UPPER 20S TUESDAY NIGHT AND WEDNESDAY NIGHT. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 330 PM MONDAY...HIGH PRESSURE OVERHEAD THURS MORNING WILL SHIFT OFF SHORE THROUGH THE DAY. A VERY WEAK RETURN FLOW WILL SET UP AT THE SFC WHILE WINDS ALOFT REMAIN MORE WESTERLY AS RIDGE SHIFTS EAST LEAVING MORE OF A ZONAL FLOW IN THE MID LEVELS. THE WESTERLY DOWNSLOPE FLOW WILL HELP TO KEEP CONDITIONS DRIER THROUGH MOST OF THE DAY...BUT MODEST MOISTURE RETURN WILL COME LATE DAY AS MINOR PERTURBATION IN THE MID LEVELS MOVES EAST ACROSS THE CAROLINAS. DRIVES A COLD FRONT EAST INTO THE CAROLINAS. PCP WATER VALUES SHOULD REACH UP NEAR .75 INCHES BY THURS EVE. HAVE INCLUDED LOW END POPS THURS NIGHT BUT DO NOT EXPECT MUCH IN THE WAY OF QPF. THE DOWNSLOPE FLOW WILL HELP TO BRING COLD MORNING TEMPS BACK UP TOWARD NORMAL. CLOUDS AND MOISTURE WILL KEEP OVERNIGHT LOWS WELL ABOVE FREEZING THURS NIGHT AND THEREFORE NO MENTION OF MIXED PCP. THIS COLD FRONT WILL MOVE EAST THROUGH THE CAROLINAS THURS NIGHT THROUGH EARLY FRI. ANOTHER SHOT OF COLD AND DRY AIR WILL COME ON FRI AS HIGH PRESSURE BUILDS DOWN FROM CANADA. THE WARMER START TO THE DAY ON FRI AND SUNSHINE WILL COMBINE TO PUSH TEMPS UP INTO THE 50S MOST PLACES. DEEP NW-N FLOW WILL DEVELOP BY LATER ON FRI AS MID TO UPPER TROUGH MOVES OFF SHORE. CAA THROUGH FRI NIGHT WILL BRING TEMPS BELOW FREEZING WITH CLEAR AND COOL CONDITIONS EXPECTED. SUBSIDENCE AND DRY AIR WILL EXIST THROUGH MOST OF SATURDAY AS HIGH PRESSURE EXTENDS DOWN FROM THE NORTH AT THE SURFACE. COLUMN WILL REMAIN DRY WITH PCP WATER VALUES DOWN LESS THAN A QUARTER OF AN INCH. OVERALL COOL AND SUNNY DAY ON SATURDAY. NEXT SYSTEM WILL APPROACH THE CAROLINAS ON SUNDAY AS HIGH PRESSURE SHIFTS OFF THE COAST. AS MID TO UPPER TROUGH SHIFTS EAST A DEEPER SW RETURN FLOW WILL SET UP BRINGING CLOUDS AND INCREASED CHC OF SHOWERS THROUGH EARLY NEXT WEEK BEFORE A COLD FRONT MOVES THROUGH LATE MON. SOME DISCREPANCIES BETWEEN ECMWF AND GFS WITH ONE BRINGING A SOUTHERN STREAM LOW ACROSS THE SOUTHEAST AND ONE SHOWING A NORTHERN STREAM LOW MOVING EAST. EITHER WAY...IT LOOKS LIKE CLOUDS AND PCP WILL BE BACK IN FORECAST FOR SUNDAY AND MONDAY. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 06Z...EXPECT VFR AT THE TERMINALS...EXCEPT FOR PERIODS OF MVFR CEILINGS/VSBYS IN SCATTERED SHOWERS AT KILM OVERNIGHT. STRONG LOW PRESSURE WELL N OF THE AREA...WILL CONTINUE TO MOVE AWAY. LATEST RADAR DEPICTS SHOWERS WRAPPING AROUND THIS DISTANT SYSTEM AS FAR SOUTH AS THE KILM TERMINAL. OTHER THAN PERIODS OF MVFR DUE TO LOW CIGS AND VSBYS IN SHOWERS AT KILM OVERNIGHT...EXPECT VFR OVERNIGHT. A SLOW CLEARING TREND WILL DEVELOP FROM SOUTHWEST TO NORTHEAST... EVENTUALLY OVERSPREADING THE TERMINALS...FIRST ACROSS KFLO OVERNIGHT AND THEN ACROSS THE OTHER SITES DURING THE MORNING. WEST-NORTHWEST WINDS AOB 12 KT WITH GUSTS UP TO NEAR 20 KT WILL PERSIST INTO THIS AFTERNOON. WINDS WILL BECOME LIGHT AND VARIABLE BY EVE. EXTENDED OUTLOOK...VFR WILL PREVAIL TUE THROUGH SAT. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM MONDAY...INTENSIFYING LOW OFF THE DELNJ COAST LATE THIS EVENING...WILL TRACK SLOWLY TO THE NNE OVERNIGHT AND TUE. WITH THIS STORM EXPECTED TO BOMB...THE SFC PRESSURE PATTERN AND TIGHTENING SFC PRESSURE GRADIENT WILL PRODUCE NW WINDS IN THE 15 TO 25 KT RANGE WITH GUSTS UP TO 30 KT REMAINING POSSIBLE. THE THINKING IS THAT THE MAJORITY OF THE MODELS HAVE UNDERDONE/UNDERFORECAST THE WINDS OVERNIGHT ACROSS THE LOCAL WATERS. AS A RESULT...HAVE PUSHED FORWARD THE ENDING OF THE SCA FROM TUESDAY MORNING TO MIDDAY TUESDAY. WITH AN OFFSHORE WIND TRAJECTORY...IE. VERY LIMITED FETCH FOR WAVES TO BUILD UPON...SIGNIFICANT SEAS WILL RANGE FROM 3 FT OR LESS ACROSS THE NEAR SHORE WATERS LESS THAN 10 NM...AND 4 TO 6+ FT ACROSS THE OUTER WATERS FROM 10 TO 20 NM OFF THE COAST. PREVIOUS DISCUSSION................................... AS OF 315 PM MONDAY...DEEPENING LOW PRESSURE OFF THE VIRGINIA COAST WILL BECOME A MONSTER STORM SYSTEM FOR NEW ENGLAND TOMORROW. FOR THE CAROLINA COAST THIS SHOULD SIMPLY BE A WIND EVENT. NORTHWEST WINDS CURRENTLY 15-20 KNOTS SHOULD INCREASE TO 20-25 KT WITH GUSTS TO 30 KNOTS POSSIBLE DURING THE PERIOD OF STRONGEST COLD ADVECTION OVERNIGHT. MODEL CONSENSUS IS HIGH WITH THIS EVENT. SEAS ARE EXPECTED TO BUILD TO 4-6 FT IN VERY CHOPPY SHORT PERIODS WITH THE OFFSHORE WINDS. OUT AT THE FRYING PAN SHOALS BUOY (NEARLY 35 MILES OUT) SEAS COULD BUILD TO 7-8 FT! SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 315 PM MONDAY...WITH THE NOR`EASTERLY SLOWLY MOVING FROM AWAY FROM THE VIRGINIA COAST WINDS WILL BE FROM THE NORTHWEST ON TUESDAY AND THEN NORTHERLY ON WEDNESDAY. WINDS SPEEDS ARE EXPECTED TO RUN AROUND 15 TO 20 KNOTS AND MAINTAIN THERE OFFSHORE TRAJECTORY SO SEAS WILL RANGE FROM 2 TO 5 FEET ON TUESDAY AND THEN DIMINISH TO 1 TO 4 FEET ON WEDNESDAY. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 330 PM MONDAY...WINDS WILL BE LIGHT AND VARIABLE THURS MORNING WITH HIGH PRESSURE OVERHEAD...BEFORE SHIFTING AROUND TO THE SW AS HIGH PRESSURE SHIFTS FURTHER EAST AND NEXT SYSTEM APPROACHES FROM THE WEST THURS NIGHT. THESE INCREASING SW WINDS WILL VEER AROUND THROUGH THURS NIGHT INTO EARLY FRI AS COLD FRONT MOVES EAST. NORTHERLY WINDS WILL VEER AROUND SLOWLY THROUGH FRI INTO SATURDAY REMAINING UP TO 15 TO 20 KTS IN TIGHTENED GRADIENT FLOW BETWEEN DEPARTING LOW PRESSURE IN THE NORTH ATLANTIC AND HIGH PRESSURE REACHING DOWN FROM THE GREAT LAKES. NORTHERLY WINDS WILL SHIFT AROUND BECOMING MORE EASTERLY AND ON SHORE SAT NIGHT AS HIGH PRESSURE NORTH OF AREA SHIFTS EAST. SEAS WILL INCREASE AHEAD OF FRONT AND THEN IN INCREASED NORTHERLY FLOW THROUGH FRI INTO SAT BUT FOR NOW IT LOOKS LIKE SEAS SHOULD TOP OUT AROUND 5 FT REMAINING BELOW SCA THRESHOLDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TUESDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...DCH/TRA SHORT TERM...DRH LONG TERM...RGZ AVIATION...SGL/RJD

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